084 
 WTPZ42 KNHC 080236
 TCDEP2
 
 Hurricane Aletta Discussion Number   9
 NWS National Hurricane Center Miami FL       EP022018
 900 PM MDT Thu Jun 07 2018
 
 Based on how Aletta looked last evening, it would have been hard to
 imagine the cyclone improving in structure so drastically.  Yet, the
 hurricane has continued to improve in organization and has deep
 convection with cloud tops as cold as -85C completely surrounding a
 ragged, cloud-filled eye.  Dvorak classifications have increased to
 T5.0/90 kt from TAFB and SAB, while objective guidance from the
 UW-CIMSS ADT and SATCON have increased more modestly to between
 75-80 kt.  Based on these data, Aletta's current intensity is
 estimated to be 85 kt.  Since Aletta's estimated intensity 24 hours
 ago was 45 kt, the cyclone's recent strengthening meets the
 criterion for rapid intensification.
 
 Aletta appears to have another 24 hours or so before vertical shear
 gradually increases, and 48 hours before sea surface temperatures
 become marginal to support further strengthening.  Therefore,
 additional intensification is anticipated during the next 24 hours,
 and the new NHC official forecast brings Aletta's intensity to just
 below major hurricane status.  The chance of a another 20-kt
 increase in the next 12 hours is just under 50 percent, so it's not
 out of the question that Aletta could reach major hurricane
 strength on Friday.  Weakening is anticipated to begin by 36 hours,
 and the weakening rate should be rather fast in 3 to 4 days due to
 stronger shear and colder waters.  The updated NHC forecast is
 close to HCCA and the intensity consensus for the first couple of
 days but then is above most of the guidance after 48 hours to
 maintain continuity with the previous forecast.  The GFS and ECMWF
 models show Aletta's convection dissipating in about 4 days, so the
 NHC forecast now calls for the cyclone to become a remnant low by
 day 5.
 
 Aletta is being steered slowly west-northwestward, or 300/5 kt,
 around a mid-level ridge located over northwestern Mexico and
 toward a break in the ridge located west of the Baja California
 peninsula.  Because the hurricane has strengthened more than
 previously expected, it has taken a jog toward the north, closer to
 where more aggressive models such as the GFS and HWRF had been
 predicting.  With the additional strengthening anticipated, the NHC
 track forecast largely discounts the ECMWF solution, which is an
 outlier to the south of the other models, and lies farther north
 close to the TVCE model consensus and HCCA models.
 
 FORECAST POSITIONS AND MAX WINDS
 
 INIT  08/0300Z 15.6N 110.3W   85 KT 100 MPH
  12H  08/1200Z 16.0N 111.0W   95 KT 110 MPH
  24H  09/0000Z 16.6N 111.9W   95 KT 110 MPH
  36H  09/1200Z 17.2N 112.8W   90 KT 105 MPH
  48H  10/0000Z 17.8N 113.7W   75 KT  85 MPH
  72H  11/0000Z 19.1N 115.4W   50 KT  60 MPH
  96H  12/0000Z 20.0N 117.5W   30 KT  35 MPH
 120H  13/0000Z 20.5N 119.5W   20 KT  25 MPH...POST-TROP/REMNT LOW
 
 $$
 Forecaster Berg